The development of tooth whitening techniques has been taking place for well over 100 years. It is well known that the teeth can be effectively bleached by the use of hydrogen peroxide as the bleaching agent, and it is proven that, in general, tooth-whitening preparations having higher concentrations of bleach are more effective in whitening the teeth than those of lesser concentration. Thus, increasing concentrations of the bleaching agent in the bleaching gives rise to a more rapid bleaching action. The problem with the higher concentrations of bleaching solutions is that they have been proven to be painful to endure, and injurious to oral tissue, including blistering and severe discomfort to the gingiva (gum) and other soft tissue present in the oral cavity. It is well documented that oral rinse preparations of hydrogen peroxide having concentrations greater than 6% are dangerous for use in the human oral cavity, since exposure of the oral soft tissues for times on the order of seconds, has been demonstrated to cause immediate injury to the gingival and soft tissue of the human oral cavity. In general, it has been well established that the greater the concentration of hydrogen peroxide oral rinse, the faster and more severe this burning affect to the gingival and soft tissue after exposure to these oral rinse solutions. This safety issue has been the barrier and challenge to the development of tooth whitening techniques.
Tooth whitening using aqueous, or ethereal solutions of extremely high concentration of hydrogen peroxide (25%-35%) are well established as the fastest and most permanent methods available, today. These treatments require professional guidance and care, and are typically carried out in the dental office by a highly trained dental professional. This method is referred to as vital bleaching, and is tedious, and dangerous if carried out without professional application. Vital bleaching requires physical protection of the gums from exposure to the highly concentrated bleach solution (gingival dam). The dental professional custom fits a plastic damming structure around the gingiva, also places a retractor inside the lips and then lifts the lips away from the front surfaces of the teeth to keep the inside of the lips and other oral soft tissue from contact with the powerful bleaching solution. These techniques are necessary to avoid the inevitable and immediate sharp pain and burning sensation that would take place immediately without such, and also to minimize damage to the gingiva and oral soft tissue due to the aggressive burning of the tissue from the concentrated hydrogen peroxide bleach. This method has been shown to be the most effective tooth whitening method available, but is limited in its usefulness, since it must be performed by the dental professional, and requires 1-6 visits to the dental office and takes at least an hour to perform each visit, and cost ranges between $500 to $3,000 USD; rather expensive and time consuming for the average person. A popular in-clinic vital bleaching method uses heat or UV light to activate the peroxide, bleach in situ and is named Zoom Whitening.
A strong desire for do-it-yourself tooth whitening methods and products exists, as evidenced by the current market popularity of many do-it-yourself products commercially available. One such product is comprised of a viscous bleaching gel contained in a professional or non-professionally fitted plastic tray, designed to provide a reservoir for the bleach as a viscous gel, and to encase the upper or lower teeth where whitening is desired. The method has the bleach in a tray to minimize exposure to the sensitive tissue. The gel form of the hydrogen peroxide bleach has the advantage in minimizing discomfort to the user, in that the exposure of the bleach to the enamel is slow due to the gel's high viscosity, and even if a leak occurs and the bleach touches the sensitive tissue, the concentration of the bleach is much lower than those employed by the vital bleaching technique. Some of the popular tray method products include Den Mat Night White, and Opalescence (3.5-8% bleach [10%-25% urea hydrogen peroxide, respectively]). The method has the user apply the tray daily for periods ranging from 20 min to 12 hours for at least 10-14 sequential days. This method has the advantage to the vital bleaching method because it can be done in the privacy of one's home and achieves reasonably good results. It uses gelled forms of bleaching solutions that are quite viscous, and more concentrated that what is available OTC for safe oral rinse application (1.5%-3% hydrogen peroxide), but much less concentrated than the vital bleaching method (25%-35% hydrogen peroxide). Typically, the concentrations of peroxide bleach in these tray method gels are on the order of 3.5% peroxide to about 8% peroxide, where urea is used as a stabilizing agent. A 10%-25% urea hydrogen peroxide gel provides for 3.5%-10% hydrogen peroxide activity, respectively. The tray method suffers because it is uncomfortable, time consuming and messy to use. Since the tray is fashioned to have the gel exposed to the front surfaces of the teeth, it only results in the bleaching of the front portions of the teeth encased in the tray. The method does not bleach teeth that are not encased by the tray, nor does it bleach the back and side areas of such teeth. In summary, the tray method suffers from the requirements that: (a) it must be performed multiple times (10-60); (b) it must stay on for an extended period of time each use (20 min-12 hr); (c) it is accompanied with some discomfort due to poor fitting trays, and dehydration of the teeth, and is messy to use, and; (d) in most cases still requires an initial visit to the dental professional to create the tray and provide instructions, and; is costly, the price ranging from 300-600 USD, and; (e) it does not provide the ability to bleach the inside portions, and hard to reach side portions of the teeth.
A similar technology is the “strip matrix” in which the hydrogen peroxide bleach solution of 6% (Crest Whitestrips, Procter and Gamble) or 14% (Crest Whitestrips Supreme, Procter and Gamble) is a thin layer on a plastic strip that is applied directly to the surface of the teeth. Bleaching of the front portions of the teeth takes place slowly over time by having the hydrogen peroxide slowly leak out of the strip matrix directly onto the surface of these teeth. The strip matrix minimizes exposure of the bleach to the sensitive tissue, since it does not touch the soft tissue and gingival tissue. Typically, the treatment requires the user to keep the strip on the teeth for about 20 minutes, repeating this procedure once a day for at least 5-14 days to see significant results. The technique has been reported as less uncomfortable than the “tray method”, with similar tooth whitening results. Significant disadvantages are the length of time needed to get the desired whitening, the requirement for multiple uses, and the need for privacy during usage, since the wearing the strips in public has social disadvantages and are, in general, inconvenient, and also the inability to bleach the areas in between the teeth, and the back portions of the teeth.
Tooth whitening toothpaste compositions are also commercially available, but most of these use abrasion rather than bleaching agents for the tooth whitening action. Those tooth whitening toothpaste preparations that do include bleaching agents have the bleach at very low concentrations. The effectiveness of tooth whitening toothpaste products are, at best, none to moderate.
Oral rinse solutions have been commercially sold as tooth whitening and breath freshening mouthwash products (one current commercial example is Crest Tooth Whitening Oral Rinse), and similar solutions have been utilized as a breath freshening and tooth whitening spray (U.S. Pat. No. 5,611,690). These oral rinse methods are limited in the amount of the bleach that can be utilized in the bleaching solution, which in these cases are also breath freshening solutions, since oral rinses having greater than 3% are known to be dangerous to the user if left in the mouth for much longer than 15 seconds. In Europe and Canada, it is illegal to dispense tooth whitener or breath freshening products having concentrations of hydrogen peroxide greater than 1.5%, and 3% respectively. Thus, any tooth whitening effect of these types of oral rinse solutions is minimal, at best. Effective tooth bleaching action for these types of products would, in concept, require much longer exposure times than is practically possible for these lower concentrated solutions of bleach. Since the decomposition of peroxide in the oral cavity would most likely occur before any appreciable tooth whitening, and the corresponding pain and possibly injury to the user most likely would be a result of these long durations of exposure, these oral rinse tooth whitening methods are severely hampered.
One method to overcome the extremely long duration required to achieve any appreciable tooth whitening of oral rinse breath freshening and, hypothetically, tooth-whitening solutions, is to increase the frequency of usage. Such a method was taught by Summers et al. in U.S. Pat. No. 5,611,690, where he teaches a spray method for application of these types of oral rinse solutions many times throughout the day (over 7 treatments a day). Any tooth whitening efficacy of this spray method is severely hampered due to the low strengths of hydrogen peroxide, and due to the inconvenience of having to use it many times throughout the day in order to achieve any appreciable tooth whitening. The tooth whitening results described by his teachings are not reported in a manner consistent with scientific standards, but rather anecdotally, and based on the formulas tested, would be expected to be moderate, at best since the example provided has less than 3% [H2O2]. Another important drawback to the teachings of Summers et al. is the danger to the user as a result of misdirected spray. It is highly probable that the spray mist containing the peroxide and breath freshener, according to his teachings using the spray apparatus detailed in his invention, may easily be misdirected to non-targeted areas such as facial tissue, and eyes, and clothes. It is well known for solutions of hydrogen peroxide of tooth bleaching strength (1.5%-40%) that contact with the lips and skin will be painful and injurious to the user due to the immediate burning that takes place on such tissues. Contact with the eyes with the spray mist comprised of hydrogen peroxide causes serious burning, sometimes irreversible and even blindness can occur. Irreversible damage to clothing fabric is imminent upon contact with hydrogen peroxide solutions (or spray mist forms of the solutions)—even at lower concentrations of hydrogen peroxide provided, by example in U.S. Pat. No. 5,611,690.
The rationale for formulating these breath-freshening bleaching solutions provided by example in the spray taught by Summers et al. was, most likely, based on the understanding of the tooth whitening and oral hygiene art before the present invention. That is, since no evidence had been provided by the teachings of the tooth-whitening and oral care art to suggest otherwise, hydrogen peroxide solutions having concentrations greater than 3% were considered as dangerous agents for use as oral rinses in the human mouth and, therefore, were considered dangerous for use as an oral spray. As a direct result of this wisdom, the obvious concentration of hydrogen peroxide for employment in the teachings of Summers et al. was those of accepted oral compatibility as oral rinse solutions, i.e., less than 3% hydrogen peroxide.
The need exists for a tooth whitener that is convenient, safe and effective, without the disadvantages of the prior methods, which are the following: (a) the high cost and inconvenience of professional application of highly concentrated solutions of bleaching agent (vital bleaching method) to achieve the optimal tooth whitening results; (b) the high probability of serious injury resulting from non-professional application of the higher concentrations of hydrogen peroxide, including the vital bleaching method and spray method of Summers et al.; (c) the inconvenience that the user must endure with the spray method taught by Summers et al. due to the high frequency of usage required for, at best, poor to moderate tooth whitening results; (d) the long duration of contact with the bleaching agent required by the tray and strip methods and the corresponding inconvenience engendered; (e) the increased discomfort effected to gingiva and soft tissue of the oral cavity by the vital bleaching, tray and strip methods; (f) the inconvenience of multiple uses or socially unacceptable paraphernalia such as a tray or strip, (g) the lack of bleaching activity on the non-front surfaces of the teeth.
Periodontal diseases, including gingivitis, are a major contributor to ill health in the United States and worldwide. Periodontal diseases if left unchecked can cause the loss of teeth, and most likely will lead to an array of systemic diseases and maladies, and many of these diseases, unfortunately, will ultimately result in serious debilitation or in many cases, death. Preventive treatments for periodontal diseases include antibacterial topical solutions or oral rinses, in addition to a well-practiced regimen of good oral hygiene comprised of tooth brushing and flossing. Remedial treatments for periodontal diseases include scaling and root-planning procedures carried out in the clinic by the periodontist, and in severe cases, removal of the diseased tooth body. Another well-accepted method of prevention and remedial treatment for gingivitis (early stages of periodontal disease) is that described by Dr. Keyes (known as the Keyes technique), where a mixture of baking soda and hydrogen peroxide are applied directly to the teeth (hard tissue) and gums (soft tissue), usually by a tooth brushing methodology. The results obtained from such method for the prevention and remediation of early stage periodontal disease is moderate to significant, however, this Keys methodology suffers from being rather inconvenient and fowl tasting.
The need exists for a convenient and effective means to safely and effectively prevent and remediate periodontal diseases.
Halitosis (oral malodor) is another common oral ailment affecting millions of people worldwide. The main cause of halitosis is the presence of sulfides and amino-based compounds generated as metabolic products of certain anaerobic oral bacteria. It is the sustained ill-growth of certain oral bacteria that thrive in the pockets of the gingival that give rise to the halitosis problem. Most of these bacterial species are also important for the incidence of gingivitis and periodontal diseases. Thus, controlling the ill-growth of certain anaerobic bacteria that thrive in the pockets of the gingiva where oxygen supplies are minimal is important, since such control would most likely result in an increase in health for the gingiva and a less odiferous oral cavity. This benefits the user chemotherapeutically by aiding the prevention of serious systemic and oral ailments, and aesthetically by providing the user with a confident and healthy smile. The reduction of such bacteria and bacterial chemical metabolic by-products such as odiferously unpleasant oral sulfides and amines, have been achieved to some degree by employing a regiment of daily usage of oral rinses including such drugs as chlorhexidine, and/or lesser active agents such as mineral spirits, zinc or copper salts. The Keyes technique has also been employed to address the reduction in halitosis causing agents. All of these techniques suffer from the inconvenience of the requirement that they are used in the home or office, which limits the number of times the user may employ these treatments throughout the day. It is the frequency of usage that gives rise to the effectiveness in many of these agents and techniques, so lack of usage gives rise to lack of significant results.
The need exists for an oral preparation that is not professionally administered and that is convenient to use, and is safe and effective in reduction of oral anaerobic bacteria and the chemical agents of halitosis.